Dissertation about Josef Marek is the first biography of a Czech architect living and working in Slovakia during the period between the wars, which was written as part of doctoral studies at the Faculty of Architecture STU. Josef Marek, a native of village Petrovice in Moravia, studied architecture at the Academy of Fine Arts in Prague, with the founder of modern Czech architecture - Jan Kotěra. Shortly after graduation he came to Slovakia, to take part, together with his classmates from the Academy, in developing further the modern architecture in our country. His biography brings knowledge of a much wider range of structures, than was hitherto known. With regards to projects we knew for quite some time the paper presents information in a completely new context, such as analysis of the competition for the construction of a protestant church in Trnava. To clarify the forming of his attitude to the ideas of modern architecture was in turn reinforced by examination of industrial architecture sketches that we found in his estate in Brno. The other two key chapters of the work address the most important issues of that particular historical period - housing and urban planning.